The present invention concerns a parts transfer method and apparatus for use in selecting a single part from a group of such parts and more particularly the invention concerns method and apparatus for selecting a single wire lead for use as a lamp electrode from a group of such parts.
An existing feeding device for ceramic metal-halide lamp electrodes uses a vibratory bowl feeder to funnel the individual parts onto a track At the end of the track, an escapement singlates the parts and a prior art vacuum pick-and-place unit pushes into the end of the track to pick one electrode up at a time. The existing feeding device appears to be functionally limited to parts no smaller than 0.012 inches in diameter. Attempts to use current systems with smaller diameter electrodes causes misfeeds, parts to fall onto the floor, and ultimately, prohibitive scrap and production delay expenses.
The electrode tips for a future ceramic metal-halide lamp require shank diameters approaching 0.005 inches and lengths approaching 2.5 millimeters. There is thus a need for a feeding system capable of accommodating electrodes of at least this reduced size.
The present invention addresses the need to singulate and feed small electrodes as part of a ceramic metal-halide lamp production process.
The apparatus, constructed in accordance with an exemplary embodiment of the invention, singulates and feeds lamp electrodes according to the method of the present invention includes, an electrode feeder, a fixture, a catch tray, and a drive mechanism. The electrode feeder, supplied by a bulk containment feeder, feeds lamp electrodes to a feeder exit. The fixture defines an upper surface having a generally apex shape, such upper surface having machined therein holes to catch some of the electrodes as they fall from the electrode feeder exit. A vibrating catch tray is mounted under the fixture, and has a return path to the bulk containment feeder. The driving mechanism is attached to the fixture, for delivering electrodes to a location removed from the electrode feeder exit.
The design and mass production of ceramic metal-halide lamps is currently constrained by electrode size. Any attempt to use current singulation and feeding systems with smaller diameter electrodes causes prohibitive scrap and production delay expenses. The present invention allows for high-speed mass production of ceramic metal-halide lamps with electrodes at least as small as 0.005 inches in diameter and 2.5 millimeters in length.
In one embodiment of the invention, an electrode feeder is mounted such that the feeder exit is positioned vertical from, but not in contact with, the apex shape of the fixture""s upper surface. When the electrodes exit the feeder, they fall and contact the fixture""s upper surface. The fixture apex may form a narrow ridge, the horizontal upper surface of which is machined with vertical holes larger than an electrode shank diameter, but smaller than an electrode coil diameter, and of a depth less than an electrode length.
The machined holes will catch falling electrodes that contact the ridge in a near vertical orientation. Once the electrode is caught, the bottom edge of the electrode coil rests against the upper fixture surface, and the electrode shank is suspended within the machined hole.
Any electrodes not caught will fall to either the inside or outside of the fixture""s apex, and are gathered by a vibrating catch tray. The fixture""s lower surface is machined to include internal pass-through voids to allow electrodes to fall into the catch tray. The fixture is machined and finished in such a fashion to prevent the collection of electrodes or portions of electrodes on any surface outside the apex vertical holes.
The electrodes are transported from a position where they are caught by the fixture to a location where they can be removed from the fixture. The fixture may be attached to a driving mechanism. The driving mechanism may be a motor connected to the fixture by a rotational mounting shaft.
In a second embodiment of the invention, the fixture is a ring-shaped turret. In this preferred embodiment, the turret""s upper surface forms a ring-shaped narrow ridge. The lower surface of the turret is machined to include internal pass-through voids, each partially circumscribing a center point of the ring, between the ring and the center point of the turret. In this embodiment, the turret is most preferably rotationally driven by a stepper motor, providing precisely timed sequential delivery to feeder exit point.